E115_Problem_Set_13

# E115_Problem_Set_13 - T m 50 K How does the error from this...

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e 115 Engineering Thermodynamics Fall 2009 University of California Problem set 13 Due: Monday, October 12 th , in lecture 1) (30 points) Consider the following reaction for aluminum: Al (solid) Al (liquid) a) If the above reaction occurs at T m , what can be said about Δ μ ? Why? (5 points) b) If the above reaction occurs at T m + 5 K , what can be said about Δ ? Why? (5 points) c) Estimate Δ for the above reaction for one mole of aluminum at T m + 3 K . (5 points) d) What simplifying assumptions are implicit in your estimate? (5 points) e) Do a more exact calculation of Δ for the above reaction for one mole of aluminum at T m + 3 K . Compare this to your estimate in part c). What percentage error was your estimate? (5 points) f) Repeat the estimation and exact calculation for
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Unformatted text preview: T m + 50 K . How does the error from this temperature compare to that in part e)? (5 points) The following data is given for aluminum: T m = 660 ° C Δ h m ( ) T m = 10 , 500 ± 250 J ⋅ mole-1 c P ( ) solid = 20.67 + 12.38 × 10 − 3 ( ) T J ⋅ mole-1 ⋅ K-1 c P ( ) liquid = 31 . 76 J ⋅ mole-1 ⋅ K-1 2) (10 points) The molar volumes of solid lead and liquid lead at the melting temperature of lead (600 K) are, respectively, 18.92 cm 3 and 19.47 cm 3 . Assume that these molar volumes are independent of pressure. Calculate the pressure that must be applied in order to raise the melting temperature to 625 K. The enthalpy of melting of lead at 600 K is 4,810 J/mole....
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